While the Conservative Party talk about national service or forced labour for young people, the Labour Party have hinted that they could allow 16 and 17 year olds to vote:
The Labour Party manifesto is likely to be published in early to mid-June. When it comes to electoral issues like this, it's significant for them to appear in the manifesto since the Salisbury Convention means that the Lords shouldn't block any policy that was in the governing party's manifesto. So if Labour include the policy in their manifesto and win the election, they should be able to pass this as law unless they choose to do a u-turn.
Will the manifesto include a pledge to lower the voting age from 18?
Market notes:
A pledge to hold a referendum on the issue will be sufficient for this market to resolve YES